Numerous bone conditions or spinal injury can cause painful collapse of vertebral bodies, including osteopenia (osteoporosis), vertebral hemangiomas, multiple myeloma, necorotic lesions (Kummel's Disease, Avascular Necrosis), metastatic disease and complications from steroid and non-steroidal anti-inflammatory drug (NSAID) use. Osteoporosis is a systemic, progressive and chronic disease that is usually characterized by low bone mineral density, deterioration of bony architecture, and reduced overall bone strength. FIG. 1A depicts the lateral view of typical spinal motion segments 20, with lumbar vertebrae 22, 26, and 28. In contrast, FIG. 1B illustrates a lateral view of a segment of a spinal column that has undergone a vertebral body compression fracture (VCF), as shown by the compressed middle vertebra 26′. VCFs are more common in people who suffer from these medical indications, often resulting in pain, compromises to activities of daily living, and even prolonged disability.
Degenerative and injured spinal disk rehabilitation (pharmacological or gene therapeutic) protocols that delay the progression of intradiscal diseases, or even restore disk health and disk functions, are a part of contemporary research developments and emerging standards of care. The science of spinal intervention has made great strides in recent years. On some occasions, spinal or poly-trauma patients experience VCFs that may be repaired by vertebroplasty and other spinal reconstructive means. Vertebroplasty, which literally means fixing the vertebral body, has been used in the United States since the mid-1990s to treat pain and progressive deterioration associated with VCF. Most often in this vertebroplasty procedure, a bone cement, like opacified polymethylmethacrylate (PMMA), or other suitable biomaterial alternatives or combinations, is injected percutaneously into the bony architecture under radiographic guidance and controls. The hardening (polymerization) of the cement media or the mechanical interlocking of other biomaterials serves to buttress the bony vault of the vertebral body, providing both increased structural integrity and decreased potential for painful micromotion and progressive collapse of the vertebrae and spinal column.
Bone tamps (bone balloons or Kyphoplasty™), a contemporary balloon-assisted vertebroplasty alternative for treatment of VCF, also involves injection of a bone cement into a mechanically created bone void within vertebral body. In this alternative vertebroplasty procedure, a balloon tamp is first inserted into the structurally compromised vertebral body, often through a cannula. The bone balloon is then inflated under high pressure. It is claimed that the expanding balloon disrupts the cancellous bone architecture and physiological matrix circumferentially and directs the attendant bony debris and physiologic matrix toward the inner cortex of the vertebral body vault. The balloon tamp is then deflated and removed, leaving a bony void or cavity. The remaining void or cavity is repaired by filling it with an appropriate biomaterial media, most often bone cement. In most cases, the treatment goals are to reduce or eliminate pain and the risk of progressive fracture of the vertebral body and its likely resulting morbidity, complications, and disability.
Although most of these interventional procedures are an improvement over previous conservative treatments that consisted of bed rest, pharmaceuticals, and/or cumbersome back braces, these methods still suffer from practical difficulties associated with filling the relevant anatomy with the therapeutic material. The precise direction and placement of the therapeutic media is fundamental to optimal patient outcomes. Iatrogenic injury may be reduced or eliminated by the proper application of a delivery technology. In the case of a damaged vertebral body, it is usually imperative that the injected therapeutic materials, e.g., bone cement, sufficiently fill the distal (anterior) end of the vertebral body since this is where the diseased tissue is normally located. When the delivery device enters the vertebral body from the distal end, the distal opening of the delivery device is often quickly encased and clogged with the therapeutic material. And when the delivery device is positioned proximal of the target site, however, the filling of the cavity is often compromised at the distal end.
Accordingly, it would be desirable to provide treatment systems and methods that allow for improved delivery of therapeutic material in the target treatment site.